Eligible Stage II and III breast cancer patients who have had estrogen receptor assays done on the primary cancer after modified or radical mastectomy will be studied. It is our intent to observe the effect of adjuvant chemotherapy and anti-estrogen therapy in breast cancer patients, stratified by estrogen receptor assay: A. Positive node patients, whose primary tumors are estrogen receptor positive (ER+), will be classified as to their menopausal status. Eligible premenopausal ER+ patients will be subjected to surgical oophorectomy and randomized into one of two groups. One group will be given Tamoxifen for three years; the other group will be given 5-drug chemotherapy (CMFVP) + Tamoxifen for one year to be followed by Tamoxifen alone for the next two years. B. Postmenopausal Stage II patients, who are estrogen receptor positive (ER+), will be randomized between (a) Tamoxifen alone for three years and (b) 5-drug chemotherapy (CMFVP) + Tamoxifen for one year, followed by Tamoxifen alone for two years. C. Estrogen receptor negative (ER-) Stage II patients, both pre and postmenopausal, will be treated with 5-drug chemotherapy for one year postoperatively and followed until evidence of treatment failure occurs.